HOMER Energy LLC announced today that its flagship software product, HOMER® Pro, now includes a new optimization algorithm that significantly simplifies the design process for identifying least-cost options for microgrids or other distributed generation electrical power systems. HOMER Optimizer™ is a proprietary “derivative free” optimization algorithm that was designed specifically to work in HOMER.

For over 20 years, HOMER has been a global workhorse for quickly finding economically viable options for microgrids and distributed generation systems, using a robust, well-tested, “modified grid search” algorithm. The grid search approach has benefits for users with deep experience in the microgrid field, but was challenging for new users and has been used to evaluate hundreds of thousands of systems in over 190 countries.

HOMER’s goal is to find the least cost combination of equipment for consistently meeting the electric load. The number of possible ways to combine equipment is in the thousands or tens of thousands of possibilities – so where do you begin? Each “case” that HOMER considers requires the program to chronologically simulate an electrical system for an entire year. The modified grid search approach requires a user to specify all possible options for searching, whereas HOMER Optimizer does not. All that is needed is a location, an understanding of the electrical load that needs to be served, and some estimates of costs for different possible components (for example, dollars per kW for solar photovoltaic panels). HOMER has default costs for all components, but these are only starting points.

Although the use of a more flexible algorithm like HOMER Optimizer sounds like an obvious choice for optimization software, the reality is that applying many optimization algorithms to electrical systems is often not a good fit, as the “out of the box” algorithms available require simplifications that do not hold true, leading to erroneous results (a false optimum). The traditional HOMER method is robust because it looks at all possible combinations of equipment that the user has defined and cannot get “stuck” in a false optimum.

“Over the years, we’ve had many requests to include an optimizer that did not require the user to be so specific, but all the models that we tried failed to produce systems as good as HOMER,” said Dr. Peter Lilienthal, HOMER Energy CEO and the original creator of HOMER. “So we finally developed our own proprietary algorithm that allows our users the best of both worlds. HOMER Pro can let the user be completely specific where it is required, and then let HOMER make the decision elsewhere. For example, a user may be constrained in how much solar PV can be used, because of space limitations. So they can be very specific about that, while letting HOMER search an essentially infinite space of storage sizes.”

The HOMER Optimizer can model both grid-connected and off-grid systems. It can include systems with solar photovoltaics, wind turbines, diesel generators, inverters, and batteries. Once the HOMER Optimizer has found a list of candidate systems, the user can be more specific about what sizes should be considered, and then iterate the model to better represent a realistic preliminary design. “This is the most important update in HOMER’s 24-year history,” says Lilienthal. Originally developed at the US Department of Energy’s National Renewable Energy Laboratory, HOMER has been downloaded by over 140,000 people in literally every country in the world.

HOMER Pro can be downloaded from this link. The program can be used at no cost for 30 days.